#include "../shared/MiscSupport.h"
#include "../shared/ThreadClass.h"
#include "../shared/GlobalConfigFile.h"

#include "TclObjCache.h"


std::string TclObjCache::getInfoForThreadMonitor()
{
  TclList result;
  result<<"TclObjCache"<<"cold count"<<_cold.size()<<"hot count"<<_hot.size();
  return result;
}
  
TclObjCache::TclObjCache() :
  _maxCacheSize(strtolDefault(getConfigItem("max_tcl_obj_cache_size"), 250))
{
  ThreadMonitor::find().add(this);
}

TclObjCache::~TclObjCache()
{
  assert(false && "There is no way to undo ThreadMonitor::find().add()");
}

TclObjHolder TclObjCache::create(std::string const &asString)
{
  return Tcl_NewStringObj(asString.data(), asString.size());
}

static const std::string s_clearOldValues = "TclObjCache::clearOldValues";

void TclObjCache::clearOldValues()
{
  ThreadMonitor::find().increment(s_clearOldValues);
  _cold.clear();
  _cold.swap(_hot);
  // Final state:  _hot is now empty.  _cold contains exactly what was
  // previously in _hot.
}
  
TclObjHolder TclObjCache::find(std::string const &asString)
{
  if (cacheDisabled())
    return create(asString);
  TclObjHolder &inHot = _hot[asString];
  bool hotChanged = false;
  if (!inHot)
  {
    hotChanged = true;
    if (TclObjHolder *inCold = getProperty(_cold, asString))
      // Found in _cold.  Add it to _hot so we won't delete it any time soon.
      // Leave a copy in _cold for simplicity.
      inHot = *inCold;
    else
      // Not found.  Create it and add it to _hot.
      inHot = create(asString);
  }
  // Save a copy of this value because the reference might be invalidated
  // before we need the value.
  TclObjHolder result = inHot;
  if (hotChanged && (_hot.size() >= _maxCacheSize))
    clearOldValues();
  return result;
}

TclObjCache &TclObjCache::getInstance()
{
  static __thread TclObjCache *instance = NULL;
  if (!instance)
    instance = new TclObjCache;
  return *instance;
}